The present invention relates to a rotating electric motor system capable of vibrating and a method for operating a rotating electric motor capable of vibrating having a rotor and a stator. The rotor and the stator forming a unit capable of vibrating, which allows mechanical vibrations.
There is in the prior art Japanese document 08 137555 A (Shinko Electric Co. Ltd) of May 31, 1996. This document proposes a vibration control system for motor instead of vibration control systems of the prior art that need the use of a oil pressure vibrator. The control of the motor is done by a first control loop, i.e. a speed control loop. The document also proposes a second control loop, i.e. a vibration control loop. Finally, the document clarifies that the frequency response of the speed control loop is set to a relatively low value with respect to signal F which controls the vibration frequency. Therefore, the motor is controlled by the first loop for rotating at speed N, and controlled by the second loop for vibrating at frequency F according to an amplitude xcex94N.
There is also in the prior art U.S. Pat. No. 5,191,618 from HISEY, Bradner L. wherein is described a rotating apparatus for reproducing low frequency signals and a method. The apparatus comprises a rotary acoustic radiator comprising an enclosure having a cylindrical side wall and end walls forming a cylindrical chamber. A motor is provided for rotating a rotor according to a rotary and alternating movement. The apparatus described in that patent is capable of reproducing sounds with very little distortion from a frequency of 80 Hertz to a lower frequency of around 20 Hertz within the audible frequency range.
There is also in the prior art Japanese patent No. 63-138230 describing a vibration analyzing device for automobile. The purpose of that invention is to evaluate the components of an automobile by submitting it to vibrations. To achieve such an evaluation, the front and back wheels of the automobile are placed on rollers and the automobile is run. A vibration signal is detected and analyzed, allowing the evaluation of the components of the automobile.
There is also in the prior art U.S. Pat. No. 3,677,077 from MERRYMAN, George B. describing an evaluation system of vibrations for evaluating the different vibrations of a moving vehicle. That system is characterized by a plurality of electric winding conductors. Currents are measured in the conductors and give an indication of the amplitude of the vibrations of the vehicle.
There is also in the prior art U.S. Pat. No. 4,988,979 from SASAKI, Hiroaki et al. describing an inspection system of rotating machines. First, the rotation speed wherein a physical parameter linked to the rotating machine is detected and a first corresponding signal is produced. Next, a sound pressure or a mechanical vibration produced by the rotating machine is detected and a second corresponding signal is produced. From those two signals, an evaluation of the rotating machine is performed.
The following patents and documents are also known in the prior art:
U.S. Pat. Nos.:
4,327,518
4,522,347
4,564,727
4,970,909
4,997,404
5,109,715
5,191,618
5,297,757
3,677,077
3,844,175
3,913,084
4,377,947
4,402,527
4,793,186
4,884,449
4,913,084
4,988,979
5,029,477
5,062,296
5,216,921
5,245,664
5,265,831
Publication:
The Soviet Journal of Nondestructive Testing (Trans. of Defektoskopiya), Vol. 10, No. 3, pages 301-307, May-June, 1974 (publ. March 1975)
Japanese patent Nos.:
63-138230
1-180425
3-68834
56-6181
57-538
63-088410
UK patent No.:
2,201,777
Russian patent Nos.:
241,803
368,540
None of the above-mentioned patents or documents proposes a rotating machine nor a method for operating a rotating machine capable of vibrating wherein the machine can vibrate within an audible frequency range independent from whether it is rotating or not.
An object of the present invention is to provide a rotating electric motor system capable of vibrating and a method for operating a rotating electric motor capable of vibrating wherein the electric motor can vibrate within an audible frequency range independent from whether it is rotating or not.
According to the present invention, there is provided a rotating electric motor system capable of vibrating comprising:
an electric motor having a rotor and a stator, the rotor and the stator forming a unit capable of vibrating having a first passband allowing mechanical vibrations within an audible frequency range;
a power amplifier for powering the electric motor, having a power output connected to the electric motor and a control signal input for receiving a control signal, the power amplifier having a second passband including at least the first passband; and
a signal generator for generating the control signal, the signal generator having a third passband comprising at least the first passband, the control signal having a continuous component for rotating the rotor with respect to the stator, and an alternating component for inducing mechanical vibrations in the unit capable of vibrating.
According to the present invention, there is also provided a method for operating a rotating electric motor capable of vibrating having a rotor and a stator, the rotor and the stator forming a unit capable of vibrating having a first passband allowing mechanical vibrations, the method comprising the steps of:
(a) producing a control signal having a continuous component for rotating the rotor with respect to the stator, and an alternating component for inducing mechanical vibrations in the unit capable of vibrating within an audible frequency range;
(b) producing a power signal in response to the control signal produced in step (a), for powering the electric motor; and
(c) powering the electric motor with the power signal for vibrating the electric motor in response to the alternating component of the control signal and rotating the rotor in response to the continuous component of the control signal.
Other objects, advantages and other characteristics of the present invention will be readily apparent upon reading of the following non restrictive description according to preferred embodiments described with reference to the drawings.